Cement-furnace.



TRAOHSLER.

CEMENT FURNACE.

APPLICATION FILED MAY 23, 1910.

Patented Oct. 29, 1912.

HEINRICH TRACHSLER, OF ZtlRICI-I, SWITZERLAND.

CEMENT-FURNACE.

Specification of Letters Patent.

Patented Oct. 29, 1912.

Application filed May 23, 1910. Serial -I\To. 562,918.

T 0 all whom 2'25 may concern Be it known that I, HEINRICH TRACHSLER, acitizen of the Republic of Switzerland, residing at Zurich, VMuhlebachstrasse 38, Switzerland, have invented certain new and usefulImprovements in Cement-Furnaces, of which the following is aspecification.

The present invention relates to a cement furnace particularly suitablefor treating large charges of material, and is particularly intended tobe heated by coal and coke in such a manner that the fuel is mixed withthe raw powdered material. The increasing of the cross section of shaftsof cement furnaces, when it is desired to treat a large quantity ofmaterial and in firing, is attended with certain difficulties. The material being burnt has a tendency to cake, and when the burning chamberis too wide it is almost impossible to loosen the caked mass; thedifliculty of supplying suflicient air to the interior of the charge isanother disadvantage.

According to the present invention, I avoid the use of shafts which aretoo wide, but obtain a sufficient supply of air to the interior and allparts of the charge by providing a special air supply shaft. Ahalfcircular or are shaped furnace is used, while the air supply shaftis situated at the side of the furnace, and the cross section of thefurnace pit is substantially half annular or are shaped, the distancebetween the walls of the shaft being equally short everywhere.

The particular feature of the furnace constituting the present inventionconsists of the special arrangement whereby the heated air may bedistributed. This distribution of the heated air is effected at twoabsolutely different zones of the furnace, namely, the clinker zone andthe calcining zone; thus two different hearths are formed in thefurnace.

I shall now particularly describe my invention, with reference to theaccompanying drawings, in which z- Figure l is a vertical section of afurnace embodying my invention; Fig. 2 is a horizontal section takenonthe line AB of Fig. 1.

According to the structure as disclosed in the drawing, the furnace pitF is of an arc shape, and is provided by the formation of a jacketingwall consisting of brick work. Air supply channels 6 are formed in thiswall, and communicate at points near the bottom of the furnace pit withthe atmosphere by means of passages b, which passages Z) pass entirelyacross the wall of the furnace so as to communicate with the pit F, asshown in the drawings. The channels Z) connect at their upper ends witha chamher 0 situated in the wall of the furnace, the arrangement ofwhich can be particularly seen upon reference to Fig. 2. The chamber ccommunicates with the furnace pit by means of channels 2' atapproximately the clinker zone of the furnace. A vertical air channel ais situated approximately concentric to the are shaped pit F and isdisposed in the jacketing wall a. The channel 6 can be closed by a slidevalve 6, which may be conveniently controlled directly from the exteriorof the furnace; the channel a communicates with cross channels f and gwhich pass radially through Wall a, so that air may be fed in twodirections from channel 6; channel 7 is situated about opposite channels2', hereinbefore referred to, and channel 9 is situated approximatelyopposite channels 6, but they must be so disposed that the channel f hasits outlet into the calcining zone of the furnace and the channel 9 hasits outlet into the clinker zone.

A slide valve h is movably arranged in the channel 6 for regulating thepassage of air, suitable means h being provided for adjusting the valvefrom outside the furnace. The channel 6 communicates at the base of thefurnace with horizontally disposed passages in, through which air may bedriven by means of a suitable blast, but the furnace may be workedwithout a blast, the ordinary natural draft being utilized. The airentering the furnace shaft from channel 9 affords the completecombustion of the coal mixed with the cement material. The zone ofgreatest heat exists somewhat above the channels 9, and in this zone theactual clinkering takes place. The carbon dioxid formed there from thefuel, and the same gas set free from the raw cement material in theregion of channel f is converted, by means of the wellknown reactionwith incandescent carbon, into carbon monoxid. In the usual constructionof cement furnaces, the carbon monoxid generated is lost, as it isallowed to escape unburnt together with the other gases. By thearrangement constituting the present invention, however, hot air isintroduced through out the whole cross section of this Zone through thepassages f and i; this air mixing with the carbon monoxid causes thecombustion of the latter, the heating effect thereof being utilized inthe calcining process.

The above described operations require a reliable regulation of thesupply of air to the interior of the furnace, and by moving the slidevalve 71, and also regulating the position of valve 6, the amount of airpassing through the channel 6 can be regulated.

In the form of construction shown, the air shaft 0 being arranged nearthe outer Walls of the furnace, enables the regulation of the air supplyto be easily effected from the exterior of the furnace. The layer ofmaterial to be burnt is of the same thickness throughout, and is suchthat air can penetrate in suflicient quantity even to the middle of thelayer. The air channel 6 is easily accessible so that the quantity ofair introduced into the inner chamber can easily be regulated from theoutside.

I claim 1. A cement furnace comprising in combination, a jacketing wallforming a furnace pit of are shaped transverse section and having alongitudinally extending air channel formed therein substantiallyconcentric to the said pit and adapted to deliver air radiallythereinto.

2. A cement furnace comprising in co1nbination, a jacketing wall forminga furnace pit of are shaped transverse section and having a.longitudinally extending air channel formed therein substantiallyconcentric to the said pit and adapted to deliver air radiallythereinto, and means actionable from the exterior side of said jacketingwall and passing transversely therethrough adjacent the air channel forcontrolling the same.

3. A cement furnace comprising in combination, a jacketing wall forminga furnace pit of are shaped transverse section, said 'jacketing wallhaving an air chamber formed therein surrounding said pit above and opento the calcining zone of the furnace pit, said chamber receiving airadjacent its upper end, and a longitudinally extending air channelformed substantially concentric to the said pit and adapted. to

K deliver air radially thereinto.

In testimony whereof I affiX my signature in presence of two wltnesses.

HEINRICH TRACHSLER.

l Vitnesses T. F. Dwrerrr, CHARLES ORTLIEB.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Iatents,

Washington, D. G.

